JPH078457A - Ophthalmological measuring instrument - Google Patents

Abstract

PURPOSE:To obtain a measured value whose reproducibility is satisfactory by providing an irradiating means for irradiating ascending/descending light for excitation toward and eye to be examined in order to obtain a fluorescent cross section image based on spontaneous fluorescence, and an image receiving means for receiving the fluorescent cross section image, based on the spontaneous fluorescence generated by irradiation of an illumination light. CONSTITUTION:When a messuring switch is depressed, an observation light source 10 is turned off, a photographing light source 12 is turned on instantaneously, and an eye 3 to be examined is irradiated with a slit illumination light for excitation. As a result, a protein component for generating spontaneous fluorescence contained in the cornea C and the crystalline lens L is excited by the slit illumination light and the spontaneous fluorescence is generated. Subsequently, an image receiving output of a two-dimensional image sensor 20 is amplified by an amplifier 24, and thereafter, a fluorescent cross section image is stored and held by an image catching circuit 25. This fluorescent cross section image is inputted to an arithmetic part 26 as a prescribed number of picture elements, and a digital numerical value of gradation. Next, the arithmetic part 26 derives the obtained fluorescent light quantity as a relative fluorescent intensity value. A result of this operation is displayed on a display part 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to autofluorescence generated by irradiating an eye to be inspected with illumination light for excitation (a protein substance present in the cornea and lens by irradiation with illumination light for excitation). The present invention relates to an ophthalmologic measuring device for measuring the fluorescence emitted by the oxidative decomposition product.

[0002]

2. Description of the Related Art It has been conventionally known that when a subject's eye is irradiated with illumination light for excitation, autofluorescence is generated from the cornea and the crystalline lens. Conventionally, a commercially available fluorophotometer is known as an ophthalmologic measuring device for measuring the autofluorescence.

[0003]

However, in this ophthalmologic measuring apparatus, the illumination light for excitation is moved from the cornea toward the crystalline lens during the measurement of the autofluorescence, so that the light from each location in the optical axis direction of the subject's eye is measured. Since the configuration is such that the autofluorescence is measured, it takes a long time to measure the autofluorescence, and the eye to be inspected moves due to involuntary eye movement during this period, so that there is a problem that the reproducibility of the measurement value is poor.

That is, since the positional relationship between the cornea and the crystalline lens of the eye to be inspected cannot be clearly identified, it cannot be determined which part of the eye to be inspected is measured, and the reliability of the measured value is lacking.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an ophthalmologic measuring apparatus capable of obtaining a measured value with good reproducibility.

[0006]

Claim 1 according to the present invention
The ophthalmic measurement device described in, in order to solve the above problems,
Irradiation means for irradiating the illumination light for excitation toward the subject's eye to obtain a fluorescence cross-sectional image based on spontaneous fluorescence, and an image receiving for receiving the fluorescence cross-sectional image based on the spontaneous fluorescence generated by the irradiation of the illumination light. And means.

In order to solve the above-mentioned problems, an ophthalmologic measuring apparatus according to a third aspect of the present invention irradiating means for irradiating the eye to be examined with illumination light for excitation having a wavelength range of 310 nanometers to 400 nanometers. And a light receiving means for receiving the spontaneous fluorescent light having a central wavelength of 440 nanometers generated by the irradiation of the illumination light.

[0008]

[Operation] According to the ophthalmologic measuring apparatus according to claim 1 of the present invention, the irradiation means irradiates the illumination light for excitation toward the eye to be examined. The eye to be inspected emits autofluorescence by the illumination light for excitation. The image receiving means receives the fluorescence cross-sectional image based on the spontaneous fluorescence.

According to the third aspect of the ophthalmologic measuring apparatus of the present invention, the irradiating means irradiates the eye to be inspected with illumination light for excitation having a wavelength range of 310 nanometers to 400 nanometers. The light receiving means receives the spontaneous fluorescence having a central wavelength of 440 nanometers generated by the irradiation of the illumination light. The autofluorescence intensity obtained by irradiating the excitation illumination light in the wavelength range of 310 nanometers to 400 nanometers has good reproducibility.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is an illumination optical system, 2 is an image receiving optical system, and 3 is an eye to be inspected. The subject is fixed to a well-known chin rest (not shown). A fixation light source 4 is provided in front of the eye 3 to be inspected, and the subject receives the measurement while fixing the fixation light source 4. The illumination optical system 1, the image receiving optical system 2, and the fixation light source 4 are integrally configured to be movable back and forth toward the subject (movable in the direction of arrow AA ′). The illumination optical system 1, the image receiving optical system 2, and the fixation light source 4 are movable in a mechanism such as a slit lamp (slit lamp microscope).
A movable mechanism between the frame and the stand is used.

In FIG. 1, an optical axis O1 of the illumination optical system 1,
The angle θ of the image receiving optical system 2 with respect to the optical axis O2 is approximately 90 degrees as in the case of performing fluorescence analysis of the extracted crystalline lens using a fluorescence spectrophotometer, but this angle θ can be arbitrarily adjusted.
That is, when the mydriasis of the eye 3 to be inspected is not sufficient, the slit luminous flux may be blocked by the iris R, and the slit luminous flux may not reach the rear part of the crystalline lens L. In such a case, the optical axis of the optical axis O1. The angle θ with respect to O2 is set smaller than 90 degrees. In this case, the optical axis of the image receiving lens, which will be described later, is inclined with respect to the optical axis O2 to receive an image according to the so-called Scheimpflug's law. The optical axes O1 and O2 are configured to be symmetrical with respect to the optical axis of the fixation light source 4.

The illumination optical system 1 has an observation light source unit 5, a photographing light source unit 6, a total reflection quick return mirror 7, a slit plate 8 and a projection lens 9. The observation light source unit 5 is an observation light source 10 including a halogen lamp or a tungsten lamp.
And a condenser lens 11. The photographing light source unit 6 is roughly composed of a photographing light source 12 made of a xenon flash, a condenser lens 13, an exciter filter 14, and a photographing illumination light amount adjusting filter 15. The condenser lens 13 and the condenser lens 11 are conjugate with respect to the quick return mirror 7.

The exciter filter 14 has a characteristic that it transmits the illumination light F (see FIG. 2) having a central wavelength of 340 to 350 nanometers and a wavelength range of 310 to 400 nanometers. Have F. This is a specific protein substance present in the cornea C and the lens L of the eye to be examined (mainly oxidized tryptophan oxidative metabolite; This is because when illuminated, it emits fluorescence in the vicinity of 420 nanometers). However, a plurality of materials having various transmission wavelength ranges are prepared so that the central wavelength and wavelength range can be appropriately changed according to the fluorescence characteristics of the protein substance to be detected existing in the cornea C and the lens L of the eye 3 to be inspected. May be.

The photographing illumination light amount adjusting filter 15 is composed of, for example, an ND filter, and the photographing illumination light amount adjusting filter 15 is an exciter filter 14 and a quick retarder.
It is inserted in the optical path between the mirror 7 and the mirror. The photographing illumination light amount adjusting filter 15 is used as an optical attenuator when the amount of received light of a two-dimensional image sensor as an image pickup element described later is saturated. When the photographing illumination light amount adjusting filter 15 is inserted, the fluorescence intensity is corrected based on this.

The slit plate 8 has a rectangular transmission hole 8a as shown in FIG. The slit plate 8 has its transmission hole 8
It is desirable to prepare various types of a having different vertical widths T and horizontal widths W. Alternatively, a slit opening / closing mechanism unit capable of variably adjusting the vertical width T and the horizontal width W used in a slit lamp or the like may be used. The projection lens 9 forms an image of the slit plate 8 in the cornea C and the lens L, and the eye 3 to be inspected is such that the slit plate 8 and the point Q of the lens L of the eye 3 to be inspected are substantially conjugate with respect to the projection lens 9. Is located. A depth diaphragm plate 16 is arranged on the front surface of the projection lens 9 as shown in FIG. Reference numeral 16a is a transmission hole of the depth stop 16.

When a half mirror is used instead of the quick return mirror 7, the observation light source 10 is turned on during observation and turned off during photographing. The quick return mirror 7 is inserted into the optical path of the illumination optical system 1 except when photographing,
At the time of shooting, it is retracted from the optical path of the illumination optical system 1 by a solenoid or the like.

The slit image of the slit plate 8 is projected onto the subject's eye 3 by the illumination of the observation light source 10. At this time, by using the depth diaphragm plate 16, an image of the slit plate 8 can be clearly formed from the cornea C to the lens L.
The same applies when the photographing light source 12 is turned on.

The image receiving optical system 2 includes a barrier filter 17, an image receiving lens 18, a total reflection quick return mirror 19, and a two-dimensional image sensor 20. The quick return mirror 19 is inserted into the optical path of the image receiving optical system 2 except when photographing and is retracted from the optical path of the image receiving optical system 2 by a solenoid or the like during photographing. The two-dimensional image sensor 20 is arranged at a substantially conjugate position with respect to the point Q of the crystalline lens L with respect to the image receiving lens 18.

As shown in FIG. 2, the barrier filter 15 has a characteristic G for transmitting spontaneous fluorescence having a center wavelength of 440 nanometers. However, a plurality of transmission wavelength ranges are prepared so that the central wavelength and wavelength range can be appropriately changed according to the fluorescence characteristics of the protein existing in the cornea C and the lens L of the eye 3 to be detected. Is preferred. Instead of the two-dimensional image sensor 20 as an image pickup means, an orthotype film (photographic emulsion) having a sensitivity at a wavelength of 400 to 500 nanometers can be used.

An observation optical system 21 is provided in the reflected light path of the quick return mirror 19. The observation optical system 21 is generally composed of a focusing screen 22 and an eyepiece lens 23. The focusing screen 22 is disposed in a conjugate position with the two-dimensional image sensor 20 with respect to the quick return mirror 19. A focusing scale 24 is provided on the focusing screen 22 as shown in FIG.
Is drawn. The sighting scale 24 has a long line 24a and a short line 24b which are in contact with the front surface Cf of the cornea C and a central fine line 24c which is orthogonal to these lines. Central thin line 24c
The intersection 24d of the thin line 24b with the thin line 24b is used for positioning the apparatus main body based on the corneal reflection image (first Purkinje-Sanson image).

That is, when the observation light source 10 is a tungsten lamp, for example, the filament is reflected on the cornea C of the eye 3 to be inspected, and the image of the filament is formed on the focusing screen 22 as the first Purkinje image. The position where the first Purkinje-Sanson image is formed is on the focusing screen 22 to the left of the center thereof. The device body is moved back and forth to bring the elongated wire 24a into contact with the front surface Cf of the cornea C.
Next, the fixation direction of the eye to be examined is changed so that the first Purkinje-Sanson image coincides with the intersection 24d.

It is assumed that the eye 3 to be inspected is instilled with a mydriatic drug before measurement, and the pupil is sufficiently opened.

To perform the measurement, the observation light source 10 is turned on,
The eye 3 to be inspected is slit-illuminated using visible light. The barrier filter 17 is retracted from the optical path of the image receiving optical system 2 during this observation.

The slit illumination light optically cuts the eye 3 to be inspected as in the case of using the photo slit lamp.
As a result, the visible cross-sectional image I of the subject's eye 3 is formed on the focusing screen 22 as shown in FIG. Further, a corneal image C ′ from the cornea C due to this illumination light is formed on the focusing screen 22. The front surface image Cf ′ of the corneal image C ′ is brought into contact with the elongated line 24a, and the positional relationship between the eye 3 to be inspected and the apparatus body is adjusted so that the corneal reflection image P coincides with the intersection point 24d. Note that L'is an image of the crystalline lens L.

Then, when the measurement switch is pressed next, the observation light source 10 is turned off and the photographing light source 12 is instantly turned on. As a result, the slit illumination light for excitation is applied to the subject's eye 3. The protein components that generate spontaneous fluorescence contained in the cornea C and the crystalline lens L are excited by the slit illumination light for excitation to generate spontaneous fluorescence.

The image receiving output of the two-dimensional image sensor 20 is input to an amplifier (preamplifier) 24, amplified and input to a video capturing circuit (video capture) 25. The image capturing circuit 25 stores and holds the fluorescent cross-sectional image I ′. The fluorescence cross-sectional image I ′ is input to the calculation unit 26 as a digital value having 512 × 512 pixels and 256 gradations.

The computing unit 26 obtains the obtained fluorescence light amount as a relative fluorescence intensity value.

This relative fluorescence intensity value is obtained by converting the fluorescence amount based on a predetermined reference value stored in advance. Then, the calculation result is the printer 2
7 is displayed and is displayed on the display unit 28.

For example, as shown in FIG. 7, the display section 28 displays the fluorescence intensity distribution H of the normal person and the fluorescence intensity distribution H'of the diabetic patient. Fluorescent intensity distribution H'of diabetic
Has a larger amount of spontaneous fluorescence than the fluorescence intensity distribution H of a normal person,
By observing this spontaneous fluorescence intensity distribution, the degree of progress of diabetes and the like can be diagnosed.

As shown in FIG. 8, several points J1, J2, J3 of the corneal image C ′ are sampled, and several points L1, L2, L3 of the crystalline lens image L ′ are sampled, and the corneal image C ′ of the corneal image C ′ is sampled. The center of curvature J4 and the center of curvature L4 of the crystalline lens image L'are calculated, the center axis M is calculated from the center of curvature J4 and the center of curvature L4, and the line densitogram is calculated as shown in FIG. It is also possible to display the fluorescence intensity distribution N in.

Further, as a parameter of the relative fluorescence intensity value, a result obtained by integrating individual point fluorescence intensity values in the fluorescence recording site in the two-dimensional image with respect to the fluorescence recording site may be used. By using such a parameter, it becomes versatile to easily determine a temporal change in relative fluorescence intensity value or comparison of individual differences.

Further, as a means for easily determining the change with time of the relative fluorescence intensity value of the same solid, a two-dimensional image is sliced based on the maximum and minimum values of the relative fluorescence intensity value to obtain equal relative fluorescence intensity. It is also possible to easily determine the measurement result by line display (isointensity line map) or by assigning a plurality of corresponding colors and displaying in pseudo color.

Although the embodiment has been described above, the present invention is not limited to this, and includes the following.

(1) As shown in FIG. 1, the photographing light source unit 6
It is also possible to adopt a configuration in which a half mirror 29 is provided in the optical path and the reflected light is received by the light receiving element 30 to monitor the deterioration of the photographing light source 12. In this case, the half mirror 29 has a high transmittance and a reflectance as low as possible. Alternatively, instead of the half mirror 29, a total reflection mirror is inserted in the optical path of the photographing light source unit 6 when the power is turned on, so that the photographing light source 1
The deterioration degree of 2 may be monitored.

(2) In the embodiment, visible light is used as the observation light source 10. However, the structure is such that a slit light beam in the near infrared is irradiated to the eye 3 to be inspected, and the focusing plate 22 of the observation optical system 21 is used.
It is also possible to provide an image pickup element at the disposition position, display a cross-sectional image on the screen, and observe the cross-sectional image displayed on the screen to determine the imaging site.

(3) In the embodiment, the photographing position is determined by observing the focusing screen 22 with the naked eye, but the cross-sectional image I formed on the two-dimensional image sensor 20 is observed,
Thereby, the imaging region can be determined.

(4) The irradiation light amount of the observation light source 10 and the photographing light source 12 can be increased or decreased by voltage control.

(5) Further, an image pickup device is provided at the position of the focusing screen 22, and a visible cross-sectional image is received by this image pickup device,
As shown in FIG. 10, the visible cross-sectional image I is displayed in parallel with the fluorescent cross-sectional image I ′ on the screen 31, or as shown in FIG. 11, the visible cross-sectional image I is changed to the fluorescent cross-sectional image I ′. It is also possible to adopt a configuration in which the colors are changed and displayed in layers.

With this configuration, the distribution position of the fluorescent substance can be easily confirmed.

(6) Further, as shown in FIG. 12, an illumination light source made of a semiconductor laser emitting a laser beam having a wavelength range of 340 nanometers to 350 nanometers instead of the photographing light source 12 made of xenon flash in the illumination optical system 1. A configuration is adopted in which 32 is provided to expand the beam diameter of the laser light by the beam expander 33, and instead of providing the slit plate 8 and the projection lens 9 to form the slit image, the cylindrical lens 34 forms the slit image. On the other hand, the observation optical system 21 of the image receiving optical system 2 is abolished,
At the time of observation, the barrier filter is removed from the optical path of the image receiving optical system 2, and the two-dimensional image sensor 20 changes the wavelength range to 3
It is also possible to adopt a configuration in which a cross-sectional reflection image of 40 nanometers to 350 nanometers is received and the imaging target portion is determined while viewing the cross-sectional image displayed on the screen 31. in this case,
Fluorescent cross-section image I based on autofluorescence with a wavelength of 440 nm
′ Is also received, but since the fluorescent cross-sectional image I ′ has a small amount of light, the cross-sectional reflected image displayed on the screen 31 has a wavelength range of 34.
It is formed by reflection of laser light of 0 nanometer to 350 nanometer. Next, the barrier filter 17 is inserted into the optical path of the image receiving optical system 2 when the fluorescence cross-sectional image I ′ is photographed. By inserting the barrier filter 17, the cross-sectional reflection image based on the reflection of the laser light in the wavelength range of 340 nanometers to 350 nanometers is cut, and the fluorescence cross-sectional image I ′ based on the fluorescence of the wavelength of 440 nanometers is received by the two-dimensional image sensor 20. The Rukoto.

The barrier filter 17 is the image receiving lens 1.
8 and the two-dimensional image sensor 20 may be provided.

The following uses of this ophthalmologic measuring device are considered as a diagnostic support means.

(1) The presence of diabetes can be determined, and it can be used for adult disease screening, group screening, and the like. In particular, it is possible to reduce the burden on the subject such as blood sampling in the conventional fasting blood glucose level measurement and the glucose tolerance test, and to perform non-invasive measurement.

(2) By measuring the autofluorescence intensity value, it is possible to predict (estimate) the stage of diabetes, and it is possible to determine whether blood glucose control is appropriate or inadequate. Can be used as

(3) By measuring the autofluorescence intensity value, active proliferative diabetic retinopathy can be predicted, and the suitability of intraocular lens insertion for a cataract eye can be determined.

(4) The presence or absence of fundus retinopathy can be predicted when the fundus of the subject's eye cannot be seen through by using an ophthalmoscope or a fundus camera because the subject's eye has a cataract.

(5) Even if the eye to be examined is clinically opaque (transparent) in its lens, it is possible to predict the progression of cataract which may occur thereafter, and also in terms of preventive medicine. It can be applied.

[0048]

Since the present invention is configured as described above, it is possible to perform autofluorescence measurement with good reproducibility.

[0049]

[Explanation of symbols]

 1 ... Illumination optical system 2 ... Image receiving optical system

[Brief description of drawings]

FIG. 1 is a diagram showing an optical system of an ophthalmologic measuring apparatus according to the present invention.

FIG. 2 is a diagram showing transmission characteristics of an exciter filter and a barrier filter according to the present invention.

FIG. 3 is a front view of a slit plate according to the present invention.

FIG. 4 is a diagram showing an example of a depth of focus diaphragm according to the present invention.

FIG. 5 is a diagram showing an example of a focusing screen according to the present invention.

FIG. 6 is a diagram for explaining aiming with a cross-sectional image formed on a focusing screen.

FIG. 7 is a diagram showing a relative comparison of spontaneous fluorescence brightness between a normal person and a diabetic patient.

FIG. 8 is a diagram showing an example for collecting a spontaneous fluorescence luminance distribution on a predetermined line.

FIG. 9 is a diagram showing a spontaneous fluorescence luminance distribution on a predetermined line.

FIG. 10 is a view in which a fluorescence cross-sectional image and a cross-sectional image based on illumination light are separately displayed.

FIG. 11 is a diagram in which a fluorescence cross-sectional image and a cross-sectional image based on illumination light are displayed in an overlapping manner.

FIG. 12 is a diagram showing another configuration of the optical system of the ophthalmologic measuring apparatus according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minor Kamiya 75-1 Hasunuma-cho, Itabashi-ku, Tokyo Topcon Co., Ltd. (72) Inventor Akio Sakurai 75-1 Hasunuma-cho, Itabashi-ku, Tokyo Topcon Co., Ltd. Within

Claims (3)

[Claims] 1. An irradiation means for irradiating an eye to be examined with illumination light for excitation to obtain a fluorescence cross-sectional image based on spontaneous fluorescence, and the fluorescence cross-sectional image based on the spontaneous fluorescence generated by the irradiation of the illumination light. An ophthalmologic measuring device having an image receiving means for receiving the image. 2. The ophthalmologic measuring apparatus according to claim 1, wherein the image receiving unit is provided with an observing unit for observing a cross-sectional image of an eye to be inspected. 3. An irradiation means for irradiating the eye to be inspected with illumination light for excitation having a wavelength range of 310 nanometers to 400 nanometers, and a spontaneous fluorescence having a central wavelength of 440 nanometers generated by the irradiation of the illumination light. Optical measuring device having a light receiving means for